Pseudagrion simalurum Lieftinck, 1948

Seehausen, Malte, Kalkman, Vincent J. & Bedjanič, Matjaž, 2025, Revision of the Pseudagrion red-group occurring in Asia west of Lydekker’s line, with description of four new species (Odonata: Coenagrionidae), Zootaxa 5587 (1), pp. 1-66 : 45-47

Pseudagrion simalurum Lieftinck, 1948 stat. nov.

Figures: 76–77 (holotype ♂, envelope); 90 (head ♂); 107 (pterothorax ♂); 124a, b (abdomen ♂); 141a–c (caudal appendages ♂).

Pseudagrion pilidorsum : Ris (1915a): 12 –13 (description ♂; Simalur);— Ris (1915b): 99 (Simalur).

Pseudagrion pilidorsum simalurum : Lieftinck (1948): 289 –290, Fig. 5 (description ♂; Simalur).

Name-bearing type specimen examined (1♂)

♂ holotype, i.1913, Sinabang, Simalur Island , Indonesia, E. Jacobson leg., RMNH, JvT no. 2854 ( Figs 76– 77) .

Lieftinck (1948: 290) stated “Described from the paratype, in the Leiden Museum”, and Lieftinck (1971: 112) designated this specimen to be the lectotype. But the description is based on a single male, thus it is a holotype.

Other specimens examined (1♂)

Indonesia, Simalur Island: 1♂, i.1913, Sinabang, E. Jacobson leg., SMF, no. 13951 .

Characterization of male

Head ( Figs 76, 90): Labrum, clypeus, antefrons and postfrons yellowish; colour of postfrons separated from vertex around the level of median ocellus; vertex reddish, with a small black patch posterior of median ocellus; large black patches posterolateral of each lateral ocellus; postocular spots reddish, bordered by black; rear of head black, but narrow yellowish along the eye margins; base and scape of antennae yellow, following segments brownish ochre.

Thorax ( Figs 76, 107): Anterior lobe of pronotum yellow-orange, this colour expanding in centre towards middle lobe, anterior margin black; middle pronotal lobe black, with a centrally divided large yellow-orange patch in in the middle, and on either side a yellow-orange patch dorsolaterally; propleuron black above, yellow-orange below and to rear; posterior lobe of pronotum yellow-orange, with its margins black; apical edge of posterior lobe convex. Pterothorax orange-reddish; middorsal carina thin black; humeral suture with a thin black stripe which is expanded to an elongate black patch at posterior quarter; interpleural suture with a black stripe at posterior quarter, and a black spot anteriorly; metapleural suture with an elongate black patch at posterior quarter; a large black marking covering at least superior one-third to half of the mesinfraepisternum; venter pale, may be covered with whitish pruinosity. Legs pale orange; femora with black stripe outside, narrowing to proximal; tibiae with black along spines; spines black.

Abdomen ( Figs 76, 124a, b): S1–2 dorsally black, laterally orange; S3–8 dorsally black, laterally and each basal annulus pale yellowish; S9 black, with anterior third red; S10 dorsally with a broad black “x”-like marking, laterally red.

Caudal appendages ( Figs 141a–c): In lateral view cercus blackish, shorter than S10; subrectangular with an open inter-lobe notch around lower third; in dorsal view apex of the superior lobe of the cercus somewhat pointed, curved inwards; an inwards directed projection around the centre of the superior lobe of the cercus; a small bulge-like interior projection is situated at the base of a ridge on the inferior lobe of the cercus, visible in dorsal and dorsolateral views, proximal edge of this projection sharply sloping; paraproct brownish-ochre, around half as long as cercus; in lateral view subtriangular and tapered with rounded apex; in dorsal view broadly rounded, concave bowl-like; bearing a small black tooth at medial edge.

Wings with 14.5–15.0 px in forewing, and 12.5–12.5 px in hindwing.

Measurements (mm): Total length (with appendages) 45.0–45.4; abdomen length (without appendages) 37.3– 37.5; hindwing 24.3–25.0; forewing 25.5–26.5; Pt in forewing 0.8–1.0; male cercus 0.5–0.6.

Female unknown.

Diagnosis

Pseudagrion simalurum belongs to the group of endemic taxa of the island chain west of Sumatra. The males are separated from most congeners occurring at adjacent islands by having S1–2 dorsally black ( Figs 76, 124a, b). This character is elsewhere shared by P. igneum ( Figs 121a, b) and P. obscurum ( Figs 123a, b)—both are very similar to P. simalurum also in the colour of the head ( Figs 87, 89a, b, 90), and the morphology of the male cercus ( Figs 138a–c, 140a–c, 141a–c). We summarised the characters for separation in table 2.

Distribution

This species is apparently endemic to Simalur Island ( Fig. 2).